Cr1−xAlxN coatings are promising candidates for advanced machining and high temperature applications due to their good mechanical and thermal properties. Recently the authors have shown that reactive magnetron sputtering using Cr-Al targets with Al/Cr ratios of 1.5 and Y contents of 0, 2, 4, and 8 at % results in the formation of stoichiometric (Cr1−xAlx)1−yYyN films with Al/Cr ratios of ∼ 1.2 and YN mole fractions of 0%, 2%, 4%, and 8%, respectively. Here, the impact of Y on thermal stability, structural evolution, and thermo-mechanical properties is investigated in detail. Based on in situ stress measurements, thermal analyzing, x-ray diffraction, and transmission electron microscopy studies the authors conclude that Y effectively retards diffusional processes such as recovery, precipitation of hcp-AlN and fcc-YN, grain growth, and decomposition induced N2 release. Hence, the onset temperature of the latter shifts from ∼ 1010 to 1125 °C and the hardness after annealing at Ta = 1100 °C increases from ∼ 32 to 39 GPa with increasing YN mole fraction from 0% to 8%, respectively.